DIMERIC ACIDS IN COSMETIC OR PHARMACEUTICAL COMPOSITIONS

Abstract: An emulsion comprises a dicarboxylic acid of formula (I) wherein R1 and R3 are each C6 to C10 alkyl and R2 to R4 are each C6 to C10 alkylene (or a cosmetically acceptable salt thereof) and an effective amount of an emulsifying agent chosen such that the emulsion may be shear-thickened in use. The compound of formula (I) is also useful in sunscreens as an anti-free-radical agent.

Description: DIMERIC ACIDS IN COSMETIC OR PHARMACEUTICAL COMPOSITIONS The present invention relates to an emulsion which can be caused to thicken in use comprising a so-called "di er acid" . The emulsion finds particular utility in cosmetics and toiletries compositions, such as sunscreens, moisturisers, skin and hair cleansers and conditioners, deodorants and antiperspirants . DE-A-3327645 (Henkel) discloses the use of dimer acids in the preparation of liposome-like vesicles. JP-A-58027636 (Shiseido) is reported as disclosing an oil-in-water type emulsion comprising dimer acid, stearic acid, cetanol, vaseline, squalene, glycerin onos t earate , monosodium-N-s t earoy lglutama t e , monosodium-N-myristoylglutoamate, propylene glycol, potassium hydroxide, sodium hydroxide and carboxyvinyl polymer. According to the present invention there is provided an emulsion comprising a dicarboxylic acid (commonly known as a 'dimer acid') of the formula (I) wherein R- j _ and R3 are each independently Cg to C^ Q alkyl and R2 and R4 are each independently Cg to C- ] _ Q alkylene; with the proviso that the acid may contain one or more unsaturated carbon-carbon bonds (or an acceptable salt thereof) ; and an effective amount of an emulsifying agent chosen such that the emulsion may be shear- thickened in use. Preferably the emulsifying agent is an alkoxylated emulsifier, suitably an alkoxylated C- j _4 to C22 alkanol, preferably an ethoxylated alkanol, preferably a polyethoxylated alkanol. Preferably R- j _ has the same chain length as R3, and R2 has the same chain length as R 4 . Suitably, R- j _, R2, R3 and R4 all have the same chain length, preferably being Cg alkyl or alkylene. Suitably, the dicarboxylic acid is producable by dimerisation of an unsaturated C^ Q fatty acid, preferably linoleic acid. It will be appreciated, however, that other methods of synthesis are possible. Particularly preferred dicarboxylic acids are those available under the trade name 'Pripure' from Unichema International. Previously these compounds have been used in the materials and petroleum industries as lubricants and rust-proofing agents. They have also been used in the preparation of liposomes. Suitably, the dicarboxylic acid is the acid available under the trade name 'Pripure 3780' from Unichema International. Preferably the emulsifying agent is a mixture of alkoxylated to C22 alkanols having different hydrophilic/lipophilic balances (HLBs) . Preferably, the emulsifying agent is a mixture of a polyethoxylated C-^ to C22 alkanol bearing a chain of 2 to 10 ethoxy groups (HLB between about 4 and about 12) and a polyethoxylated C-^ to C22 alkanol bearing a chain of 10 to 40 ethoxy groups (HLB between about 10 and about 20) . Suitably these alkanols are present in a ratio of about 2 to 1 respectively. Suitably, in each case, the alkanol is a C-^g alkanol. A preferred emulsifying agent is a mixture of POE (2) stearyl alcohol and POE (21) stearyl alcohol, suitably in a ratio of 2:1. Suitably, the emulsifying agent is present in an amount of from 0.5% to 20%, suitably 2% to 10%, preferably about 3% by weight of the emulsion. The dicarboxylic acid may be present in an amount of from 0.2% to 10%, preferably about 1% to 2.5% by weight of the emulsion. A corresponding dicarboxylic acid ester may also be present. Suitably, the emulsifying agent and the dicarboxylic acid are present in a weight ratio of 5:1 to 1:1, preferably about 3:1. Preferably, the emulsion is an oil-in-water emulsion. The emulsion is thin, stable and may show liquid crystalline phases. Preferably, the emulsion further comprises a sphingolipid such as ceramide, sphingomyelins cerebrosides or gangliosides, of plant or animal origin, suitably in an amount of from 0.05% to 1%, suitably about 0.1% by weight. Suitably, the emulsion also comprises a steroid such as the cholesterols, lanosterols, phytosterols, mycosterols and ergosterols, for example in an amount of from 0.05% to 1%, suitably about 0.15% by weight. Also useful as active components of the emulsion system are adrenocorticoids, oestrogens, androgens and bile acids. The emulsion provided by the present invention is of unusually low viscosity. It is stable and may show varying proportions of liquid crystalline phases. The rheological behaviour of the emulsion when applied to the skin or hair is also unusual. Whilst initially watery, the emulsion rapidly thickens when subjected to shearing ( 'shear-thickening' ) and dries, penetrating the skin or hair surface and providing a high resistance to further massage. Once the product has been rubbed into the skin it imparts a smooth, non-tacky finish. Application of water, however, brings a soapy cleansing effect. Once dried the skin reverts to a smooth condition. The emulsion of the present invention is particularly well-suited to use in toiletries compositions. Accordingly, the present invention also provides a toiletries composition comprising an emulsion as defined above. Preferred toiletries compositions are those for application to the skin and hair, for example sunscreens, skin cleansers, moisturisers and cosmetics products. The rheological properties provided by the emulsion of the present invention are particularly valuable in these types of compositions. The toiletries compositions of the present invention may be formulated, for example, as creams and lotions or as sprays, such as aerosols and pump sprays. The emulsion of the present invention may, if desired, be made thin enough to be dispensed as a spray and subsequently thickened by agitation, especially shearing. It will be understood that numerous further components can be added to the toiletries compositions of the present invention, for example, organic or inorganic sunscreen agents, such as microfine titanium dioxide, oils such as evening primrose oil and waxes such as mixed sphingoceryl wax. In one embodiment of the invention, the emulsion is dispensed directly to the skin and shear thickened in place on the skin. Alternatively, the emulsion maybe shear-thickened before application to the skin. Preferably, the emulsion is dispensed in the form of a spray, suitably by use of aerosolising means. Thus, the invention also provides aerosolising means, such as an aerosol spray can or pump-spray, comprising an emulsion as defined above. The present emulsion, when in sprayable form, differs markedly from other sprayable emulsions. Other emulsions are normally thick and must undergo shear thinning in order to pass through a narrow orifice such as a spray nozzle. By contrast, the emulsion of the present invention, when in sprayable form, may be made initally thin enough to pass through such a nozzle unchanged and may if desired undergo thickening only when subjected to shear on the skin or hair, for example by rubbing. The emulsion may also be dispensed by means of a "roller" mechanism, of the type commonly used for anti- perspirants and deodorants. Passage of the emulsion through the "roller" may generate a shearing action which may thicken the emulsion prior to application to the skin. Thus the invention also provides a "roller" dispenser comprising an emulsion as defined above. The present invention also provides a method of cleansing and/or moisturising the skin by applying an emulsion as defined above, and subsequently removing the emulsion, for example by washing with water. In one embodiment, the emulsion is applied as a spray and is thickened prior to removal. This method leaves the skin cleansed but also smooth and moisturised. The emulsion may be used as a medium for delivering compounds to the skin. For example, it may be used to restore the balance of lipids to skin which has become abnormal either as a result of environmental factors (such as exposure to detergents, ultraviolet irradiation or extremes of relative humidity) or through patho- physiologicai conditions such as eczema, ichthyosis and psoriasis. Thus, there is also provided the use of an emulsion according to the present invention in the treatment of such conditions and in the manufacture of a medicament for the treatment of such conditions. The emulsion may be used as a vehicle for application of sunscreens, either as a sprayable lotion or as a cream. Use of an emulsion according to the present invention may give improved substantivity to skin and hair. The emulsion may also be used to impregnate fibrous materials such as tissues to provide so-called 'baby- wipe' or 'wet-wipe' products. Tissues can be of various fibre types, either woven or non-woven and of rayon, viscose or cellulosic material. Thus, there is also provided a fibrous material impregnated with an emulsion as defined above. The properties of the emulsion of the present invention may be modified to suit various types of cosmetic product. For example, whilst normally naturally thin, the emulsion may be thickened by addition of, for example, a carbomer, montmorillonite clay, gum or alginate. The emulsion may be thickened to the point where it is no longer sprayable, and must instead be applied to the skin or hair as a cream or lotion. However, once applied, the rheological properties described above may still be obtained. Alternatively, the naturally low viscosity of the emulsion may be retained whilst the rheology is modified to produce a less extreme shear-thickening on the skin or hair. By altering the proportion of oil to water in the formulation whilst retaining the ratio of emulsifier to dimer acid, it is possible to alter the initial viscosity whilst maintaining the desired rheological properties on application to the skin or hair. It has also surprisingly been found that dicarboxylic acids ('dimer acids') of formula I above are anti-free-radical agents, especially in respect of oxygen radicals. Thus, the present invention also provides the use of a dicarboxylic acid of formula I as an anti-free-radical agent, especially an anti-oxygen free- radical agent. Anti-free-radical agents are useful in cosmetics, pharmaceuticals and toiletries compositions. When included in such compositions, they may help to reduce the build-up of undesirable free-radicals on the skin or hair. Thus, the present invention also provides a cosmetics, pharmaceuticals or toiletries composition comprising a dicarboxylic acid of formula I above. The composition may or may not be in the form of an emulsion such as the shear-thickenable emulsions described above, and may or may not comprise an emulsifying agent. Suitably the composition is substantially free of spherical bilayer or multilayer membrane vesicles. The term "cosmetics composition" as used herein includes, for example, skin creams, lotions, foundations, lipsticks and mascaras. The term "toiletries composition" as used herein includes, for example, sunscreeen compositions, after sun products, cleansing lotions, soaps, shampoos, conditioners and deodorants/antiperspirants. The term "pharmaceutical composition" as used herein includes, for example, ointments, creams, lotions, syrups and suspensions especially those for topical application. The term "substantially free of spherical bilayer or multilayer membrane vesicles" as used herein denotes a composition comprising less than about 5%, suitably less than about 1%, preferably less than about 0.1%, especially less than about 0.01% by weight of said vesicles. Particularly preferred cosmetics and toiletries compositions are sunscreen compositions. Build-up of free-radicals is particularly likely when an individual is exposed to UV radiation, and use of a sunscreen composition comprising a dicarboxylic acid of formula I above may help to reduce such build-up. The term "sunscreen composition" is used herein to include tanning lotions, sunscreens and sunblockers which are intended for topical application to provide protection against the sun's rays or other sources of untraviolet (UV) radiation. Such sunscreen compositions may or may not comprise membrane vesicles, may or may not be in the form of emulsions as described above and may comprise one or more of a variety of sunscreening agents such as microfine titanium dioxide; icrofine zinc oxide; para- aminobenzoic acids, esters and derivatives thereof (for example, 2-ethylhexyl para-dimethylaminobenzoate and the octyl ester of para-aminobenzoic acid) ; methoxy cinamate esters (such as 2-ethylhexyl para-methoxycinamate, 2- ethoxyethyl para-methoxycinamate or α, β-di-(para- methoxycinnamoyl ) -α' - (2-ethylhexanoy1 ) -glycerin; benzophenones such as oxybenzone dibenzoyl ethanes; and salicylate esters. Such sunscreening agents may typically be present in an amount of from 0.1% to 10% by weight of the composition. The compositions of the present invention may be formulated in any of the known ways for such products e.g. as milks, lotions, creams, gels, sticks or aerosols. The preferred formulation types are water-in- oil or oil-in-water emulsions such as lotions or creams. The compositions may if desired be formulated as emulsions with shear-thickening properties as described above. The water-in-oil and oil-in-water emulsions of the compositions of the present invention may comprise for example: a) hydrocarbon oils such as paraffin or mineral oils; b) waxes such as beeswax or paraffin wax; c) natural oils such as sunflower oil, apricot kernel oil, shea butter or jojoba oil; d) silicone oils such as dimethicone, cyclomethicone or cetyldimethicone; e) fatty acid esters such as isopropyl palmitate or isopropyl yristate; f) fatty alcohols such as cetyl alcohol or stearyl alcohol; or g) mixtures thereof, for example, the blend of waxes available commercially under the Trade Name "Cutina" (Henkel) . In preferred water-in-oil compositions of the present invention the oil phase comprises 5 to 40%, more preferably 10 to 30% by weight of the composition. In preferred oil-in-water compositions of the present invention the oil phase comprises 5 to 30%, more preferably 10 to 20% by weight of the composition. The emulsifiers used may be any emulsifiers known in the art for use in water-in-oil or oil-in-water emulsions. It has been found that particularly effective water-in-oil and oil-in-water compositions can be prepared by using an emulsifier or mixture of emulsifiers selected from known cosmetically acceptable emulsifiers which include: a) sesquioleates such as sorbitan sesquioleate, available commercially for example under the Trade Name "Arlacel 83" (ICI) , or polyglyceryl-2- sesquioleate; b) ethoxylated esters of derivatives of natural oils such as the polyethoxylated ester of hydrogenated castor oil available commercially for example under the Trade Name "Arlacel 989" (ICI) ; c) silicone emulsifiers such as silicone polyols available commercially for example under the Trade Name "ABIL WS08" (Th. Goldschmidt AG) ; d) anionic emulsifiers such as fatty acid soaps e.g. potassium stearate and fatty acid sulphates e.g. sodium cetostearyl sulphate available commercially under the Trade Name "Dehydag" (Henkel) ; e) ethoxylated fatty alcohols, for example the emulsifiers available commercially under the Trade Name "Brij" (ICI) ; f) sorbitan esters, for example the emulsifiers available commercially under the Trade Name "Span" (ICI) ; g) ethoxylated sorbitan esters, for example the emulsifiers available commercially under the Trade Name "Tween" (ICI); h) ethoxylated fatty acid esters such as ethoxylated stearates, for example the emulsifiers available commercially under the Trade Name "Myrj " (ICI); i) ethoxylated mono-, di-, and tri-glycerides, for example the emulsifiers available commercially under the Trade Name "Labrafil" (Alfa Chem.) ; j) non-ionic self-emulsifying waxes, for example the wax available commercially under the Trade Name "Polawax" (Croda) ; k) ethoxylated fatty acids, for example, the emulsifiers available commercially under the Trade Name "Tefose" (Alfa Chem.) ; or 1) mixtures thereof. The amount of emulsifier present in the water-in- oil compositions of the present invention is preferably in the range 2 to 10%. Preferred water-in-oil emulsifiers are anionic or non-ionic emulsifiers. The amount of emulsifier present in the oil-in-water compositions of the present invention is preferably in the range 1 to 15%, more preferably 2 to 15%. Preferred oil-in-water emulsifiers include ethoxylated fatty acids and alcohols, ethoxylated stearates and ethoxylated triglycerides and mixtures thereof. The compositions of the present invention may additionally comprise other components which will be well known to those skilled in the art. These include, for example, anti-perspirant actives such as aluminium salts, deodorant actives such as triclosan (available from Ciba-Geigy under the Trade Name "Irgasan") emollients such as isopropyl myristate or triglycerides of fatty acids e.g. lauric triglyceride or capric/caprylic triglyceride, such as the .triglyceride available commercially from Huls UK under the Trade Name "Miglyol 810"; moisturisers such as D-panthenol; humectants such as glycerin or 1,3-butylene glycol; antioxidants such as DL-α-tocopherylacetate or butylated hydroxytoluene; emulsion stabilising salts such as sodium chloride, sodium citrate or magnesium sulphate; film formers to assist spreading on the surface of the skin such as alkylated polyvinylpyrrolidone e.g. available commercially from GAF under the Trade Name "Antaron" ; thickeners such as acrylic acid polymers e.g. available commercially from B.F. Goodrich under the Trade Name "Carbopol" or modified celluloses e.g. hydroxyethylcellulose available commercially from Hercules under the Trade Name "Natrosol"; preservatives such as bronopol, sodium dehydroacetate, polyhexa- methylenebiguanide hydrochloride, isothiazolone or diazolidinylurea; sequestering agents such as EDTA salts; perfumes and colourings. It has also been found that the dimer acids defined in formula I above may help to improve substantivity of chemical sunscreening agents, especially water-soluble sunscreening agents, in the lower levels of the stratum corneum. Accordingly, in a further aspect of the present invention there is provided the use of a compound of formula I in a sunscreen formulation to improve the substantivity of the sunscreening agent to the skin. Preferably the sunscreening agent is a water- soluble sunscreening agent. The present invention is illustrated by the following non-limiting tests and examples (in which the abbreviation "POE" denotes "polyoxyethyl" and the abbreviation "PPG" denotes "polypropylene glycol"): Comparative Test A Eight test formulations (I to VIII) were prepared as follows: Test formulation I Component Concentration POE (2) stearyl alcohol (available from ICI under Trade Name "Brij 72") 2.5 POE (21) stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 Dimer Acid (available from Unichema Inter¬ national under the Trade Name "Pripure 3780") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate") 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate") 1.5 Mixture of Cτ_ 0 - 3 0 cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 Water to 100 The formulation was adjusted to pH6 with sodium hydroxide. Test formulation IX Component Concentration (w/w%) POE (2) stearyl (available from ICI under the Trade Name "Brij 72") 2.5 POE (21) steryl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate" ) 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate" ) 1.5 Mixture of Cτg_ 3Q cholesterol/nanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 Octyl methoxy cinnamate (available from Givaudan-Roure under the Trade Name "Parsol MCX") 4 Water to 100 The formulation was adjusted to pH 6 with sodium hydroxide. Test formulation III Component Concentration (w/w%) POE (2) stearyl alcohol (available from ICI under the Trade Name "Brij 72") 2.5 POE (21) stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate" ) 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate" ) 1.5 Mixture of Cτ_o_3θ cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 2-phenyl benzimidazole-5-sulphonic acid (available from Givaudan-Roure under the Trade Name "Parsol HS") 4 Water to 100 The formulation was adjusted to pH 6 with sodium hydroxide. Test formulation IV Component Concentration (w/w% ) POE (2) stearyl alcohol (available from ICI under the Trade Name "Brij 72") 2 . 5 POE stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1 , . 5 2-hexyl decyl oleate (available from Condea under the Trade Name "lsofol-16-oleate" ) 2 , . 5 2-octyl dodecyl oleate (available from Cond leeaa under the Trade Name "lsofol-20-oleate") 1 , . 5 Mixture of -,Q_3Q cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 Birch extract (available under the Trade Name "HP Herbasol Betula") 0.3 Water to 100 The formulation was adjusted to pH 6 with sodium hydroxide. Test formulation V Component Concentration (w/w% ) POE (2) stearyl alcohol (available from ICI under the Trade Name "Brij 72") 2.5 POE (21) stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate") 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate") 1.5 Mixture of C-ιo-30 cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 Water to 100 The formulation was adjusted to pH 6 with sodium hydroxide. Test formulation VI Component Concentration (w/w%) POE (2) stearyl alcohol (available from ICI under the Trade Name "Brij 72") 2.5 POE (21) stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate") 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate" ) 1.5 Mixture of ι 0 -30 cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 Dimer Acid (available from Unichema Inter¬ national under the Trade Name "Pripure 3780" 1.5 Birch extract (available under the Trade Name "HP Herbasal Betula") 0.3 Water to 100 The formulation was adjusted to pH 6 with sodium hydroxide. Test formulation VII Component Concentra ion (w/w% ) POE (2) stearyl alcohol (available from ICI under the Trade Name "Brij 72") 2.5 POE (21) stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate" ) 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate") 1.5 Mixture of CT Q _ Q cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 Octyl methoxy cinnamate (available from Givaudan-Roure under the Trade Name "Parsol MCX") 4.0 Dimer Acid (available from Unichema Inter¬ national under the Trade Name "Pripure 3780" 1.5 Water to 100 The formulation was adjusted to pH 6 with sodium hydroxide. Test formulation VIII Component Concentration (w/w% ) POE (2) stearyl alcohol (available from ICI under the Trade Name "Brij 72") 2.5 POE (21) stearyl alcohol (available from ICI under the Trade Name "Brij 721") 1.5 2-hexyl decyl oleate (available from Condea under the Trade Name "Isofol-16-oleate") 2.5 2-octyl dodecyl oleate (available from Condea under the Trade Name "Isofol-20-oleate" ) 1.5 Mixture of ι 0 _30 cholesterol/lanosterol esters (available from Croda Chemical under the Trade Name "Super Sterol Ester") 1.0 Mixture of squalane and unsaponifiables (available from Unichema International under the Trade Name "Prisorine 3759") 2.0 Propyl paraben 0.1 Methyl paraben 0.1 2-phenyl-benzimidozole-5-sulphonic acid (available from Givaudan-Roure under the Trade Name "Parsol HS") 4 Dimer Acid (available from Unichema Inter¬ national under the Trade Name "Pripure" 1.5 Sodium hydroxide 0.56 Water to 100 These formulations were tested for resistance to UV-induced free radical activity as follows; Two 20 g aliquots were taken from each formulation and each placed in separate UV-transparent plastic containers. One aliquot of each formulation was exposed to radiation from a solar simulator at a level of about 5.6 mW/cm 2 for a period of about one hour. The other aliquot was left to stand unirradiated for the same period. When irradiation was complete, the oxygen tension of each aliquot of each formulation was measured with a calibrated oxygen electrode (model 97-08-99 from Orion) . Each aliquot was tested three times at intervals of about one minute. The oxygen electrode was thoroughly cleaned with distilled water between measurements. Results are set out in Table 1. TABLE 1 Oxygen tension (ppm 0 l Formulation Measurement Unirradiated (U) Irradiated (I) Difference (U- -I) I 1 4.57 4.45 0.12 (Basic emulsion & 2 3.43 3.68 - 0.25 "Pripure" dimer acid) 3 2.07 3.16 - 0.29 II (Basic emulsion & oil 1 6.01 6.66 - 0.65 soluble sunscreening 2 5.35 6.11 - 0.76 agent) 3 4.98 5.78 - 0.76 III (Basic emulsion & 1 5.67 5.01 0.66 water soluble 2 4.71 4.41 0.30 sunscreening agent) 3 4.09 4.0 0.09 IV (Basic emulsion 1 6.26 3.41 2.85 "Herbasol" birch 2 6.00 2.90 3.10 extract) 3 5.38 2.67 2.71 V 1 5.97 3.85 2.12 (Basic emulsion) 2 5.13 3.17 1.96 3 4.67 2.81 1.86 VI (Basic emulsion & 1 5.66 5.23 0.43 "Pripure" dimer acid & 2 5.28 4.72 0.56 "Herbasol" birch 3 5.02 4.33 0.69 | extract) Oxygen tension (ppm 0 ? Formula ion Measurement Unirradiated (U) Irradiated (I) Difference (U-I) VII (Basic emulsion & 1 6.24 5.66 0.58 "Pripure" dimer acid & 2 5.48 5.03 0.45 oil soluble 3 4.94 4.67 0.27 sunscreening agent) VIII (Basic emulsion & 1 3.87 2.98 0.89 "Pripure" dimer acid & 2 3.42 2.73 0.69 water soluble 3 3.21 2.59 0.62 sunscreening agent) Reductions in oxygen tension following UV irradiation are interpreted as oxidation of unsaturated fatty acids in the emulsion as a result of free radical activity. Formulations I, VII and VIII (containing "Pripure" dimer acid) are thus seen to have an apparent anti-free-radical effect which may have a "scavenging" mechanism. Such an effect is also seen in formulations II, III, VII and VIII (containing sunscreens) but this may be due to the absorbance of UV radiation by the sunscreen component rather than by free radical scavenging action. A further set of oxygen tension measurements was taken after a further period of about 2 hours, except that only one measurement was taken for each aliquot. Results are set out in Table 2. It will be noted that the results generally follow the trends shown in Table 1 above, except that in Table 2 the known free radical scavenger, birch extract, is seen to have an apparent anti-free-radical effect. TABLE 2 Oxygen Tension (ppm O2) Formula ion Unirradiated (U) Irradiated (I) Difference (U-I) I 5.29 4.62 0.67 II 6.22 6.76 - 0.54 III 5.9 6.4 J - 0.50 IV 6.68 6.38 0.30 V 6.58 3.24 3.34 VI 6.73 6.63 0.10 VII 6.39 6.28 0.11 VIII 5.32 5.36 0.04 Comparative Test B Formulations II, III, VII and VIII from Comparative Test A above were tested as follows: In each case 40 μl of the formulation was applied to a separate 60 x 60 mm skin surface on the forearm of a volunteer. The formulation was spread over the skin surface using a glass rod and allowed to dry. Each surface was divided into four quarters (15 mm x 15 mm; designated A, B, C and D respectively. Three successive strips of skin were then removed from each of the quarters A and B by applying and then removing three circles of adhesive tape (available under the Trade Name "D-Squame") in turn from the same area of skin. After removal each portion of tape was mixed vigorously with 3 ml denatured ethanol in a small conical flask for 1 minute and the optical density (at 307 nm) of the resulting ethanolic solution was determined using a UV-visible spectrophotometer. Each skin surface was then washed with warm water (10 x 500 ml) which was run down the forearm, over the surfaces. The treated skin was allowed to dry without rubbing and then mopped gently with a single application of a paper towel. The above stripping process was then carried out on quarters C and D. In each case optical density (307 nm) reading in respect of the first circle of D-Squame" tape removed is proportional to the amount of sunscreen retained at level 1 of the stratum corneum, the second circle to the amount retained at level 2 and the third circle to the amount retained at level 3. Results are set out in Table 3. TABLE 3 Pre-wash Post-wash Formulation Level quarter % total quarter % total on sum of on sum A * B * A & B C * D * of C & D VII (Basic emulsion & 1 2.706 2.615 65 1.135 0.861 59 "Pripure" dimer acid 2 1.155 0.655 22 0.507 0.345 25 8c oil-soluble 3 0.628 0.381 12 0.304 0.229 16 suncreen) II (Basic emulsion & 1 > 3.0 2.835 65 0.956 1.064 50 oil-soluble 2 0.842 1.143 22 0.414 0.640 26 sunscreen only) 3 0.474 0.584 12 0.719 0.278 24 VIII (Basic emulsion & 1 2.004 1.441 67 0.131 0.033 30 "Pripure" dimer acid 2 0.450 0.609 21 0.045 0.040 16 & water soluble 3 0.251 0.401 13 0.143 0.152 54 sunscreen) III (Basic emulsion & 1 2.255 1.908 62 0.038 0.128 52 water soluble 2 0.609 0.560 17 0.004 0.128 42 sunscreen only) 3 1.103 0.314 21 - 0.014 0.026 4 * Optical Density (307 nm) These results suggest that the "Pripure" dimer acid increases the proportion of water soluble sunscreening agent which is retained at lower levels of the stratum corneum. Example 1 - Pump Spray delivered emulsion Oil Phase w/w % POE (2) stearyl alcohol 2.0% POE (21) stearyl alcohol 1.0% Dimer acid (available from Unichema International International under the Trade Name "Pripure 3780") 1.0% Cholesterol 0.15% Cera ide (available from Sederma, France under the Trade Designation "H03" ) 0.10% Agueous phase Aqueous sodium hydroxide/potassium hydroxide solution (2.5% : 2.5%) to pH 6.5 Water to 100% Method The oil phase components were melted together at 80°C and thoroughly mixed to produce clear dark yellow fluid. Water at approx 77°C was agitated using a Silverson mixer and the oil phase components were added at equivalent temperature. Mixing was continued at this temperature for 15 minutes. The emulsion was then stir cooled, pH adjusted to approximately 6.5 using the alkali solution, and made up to 100% with water. This product was thin enough to be pumped by an aerosol onto the skin prior to rubbing in and thickening into a cream with a dry, non-tacky, non-greasy feel. Comparative Example A Emulsions were formed as described under Example 1 above except that the ethoxylated stearyl alcohol was replaced variously by ethoxylated lauryl alcohol, ethoxylated stearic acid or ethoxylated sorbitan monostearate. The resulting emulsions failed to show the rheological properties of the emulsion of Example 1. Example 2 - Wash-off Cleanser Oil phase w, /w % POE (2) stearyl alcohol 5 . 0% POE (21) stearyl alcohol 2 . 5% Dimer acid (available from Unichema International under the Trade Name "Pripure 3780") 2 . 5% Cholesterol 0 . 375% Ceramide (available from Sederma under the Trade Designation "H03") 0.25% Aqueous phase Aqueous sodium hydroxide/ potassium hydroxide solution (2.5% : 2.5%) to pH 6 Water to 100% Method The product was formulated substantially as described in Example 1. pH was adjusted to 6 using the alkali solution prior to making up to weight. The milky product, once rubbed into the skin, leaves a dry finish which when rubbed under running water gives a slightly soapy feel. The skin is cleansed but left smooth and moisturised after use. Example 3 - Mixed 'skin lipjd' emulsion Oil phase w/w% POE (2) stearyl alcohol 2.0% POE (21) stearyl alcohol 1.0% Dimer acid (available from Unichema International under the Trade "Name Pripure 3780") 1.14% Dimer acid ester (available from Unichema International under the Trade Name "Pripure DIPD 3786") 0.5% Ceramide (available from Sederma under the Trade Designation "H03") 0.1% Cholesterol 0.15% Sterol ester 0.15% Evening primrose oil 0.2% Aqueous phase w/w% Aqueous sodium hydroxide/potassium hydroxide solution (2.5% : 2.5%) to pH 6 Water to 100% The product was formulated substantially as described in Example 1. pH was adjusted to 6 using the alkali solution prior to making up to weight. Example 4 - Sunscreen emulsion Oil phase w/w% POE (2) stearyl alcohol 2.0% POE (21) stearyl alcohol 1.0% Dimer acid (available from Unichema International under the Trade Name "Pripure 3780") 1.0% Coated microfine titanium dioxide (available from Tayca under the Trade Name "MT100T") 1.0% Aqueous phase w/w% Acrylates t-octyl propanamide copolymer (available from National Starch under the Trade Name "Dermacryl 79") 0.1% Aqueous sodium hydroxide solution (1M) to pH 6 Water to 100% Method The acrylates copolymer was suspended in water and subjected to vigorous agitation for 20 minutes. The water and oil phases were separately heated to approximately 75°C and mixed under high shear for 15 minutes. The emulsion was stir cooled, adjusted to pH 6 using the alkali solution and made up to 100% with water. Example 5 - Baby lot ion wipes Oil phase w/w % POE (2) stearyl alcohol 2.04% POE (21) stearyl alcohol 1.03% Dimer acid (available from Unichema International under the Trade Name "Pripure 3780") 1.06% Cholesterol USP 0.25% Heptamethyl nonane (available from ICI under the Trade Name "Arlamol HD") 0.75% Ceramide (available from Sederma under the Trade Designation "H03") 0.05% Aqueous phase w/w % Allantoin BPC '34 0.05% Cetrimonium bromide 0.3 % Polyhexamethylenediguanide hydro¬ chloride (available from ICI under the Trade Name "Arlagard E") 0.3 % Aqueous sodium hydroxide solution (1M) to pH 6 Water to 100% Method The oil phase was made up and mixed with water substantially as described in Example 1. Separate aqueous solutions of Allantoin and Cetrimonium bromide were added with stirring. To the resulting mixture polyhexamethylenediguanide hydrochloride was added as an aqueous solution to the required concentration. The resulting emulsion was stir-cooled, pH adjusted to approximately 6.0 using the alkali solution, and made up to 100% with water. The emulsion permeated freely through a roll of tissues to provide a 'wet-wipe'/'baby- wipe' product. Example 6 - Cream cleanser Oil phase w/w % POE (2) stearyl alcohol 5.0% POE (21) stearyl alcohol 2.5% Dimer acid (available from Unichema International under the Trade Name "Pripure 3780") 2.5% Avocado unsaponifiables (available from Croda Chemical under the Trade Name "Avocadin") 0.4% Ceramide (vegetable source) available from Bioetica, France 0.1 % Silicone fluid (20 centistokes) 0.2 % Aqueous phase w/w% Carboxypolymethylene (available from BF Goodrich under the Trade Name "Carbopol 934") 0.2% Sodium ethylenediaminetetraacetate 0.04% Aqueous sodium hydroxide solution (1M) to pH 6 Water to 100% The carboxypolymethylene and sodium ethylenediamine tetraacetate were predissolved using Silverson mixing (30 minutes) in approximately 80% of the final volume of water, to provide an aqueous phase. The oil phase was made up and mixed with the aqueous phase substantially as described in Example 1. The resulting emulsion was stir-cooled, pH adjusted to approximately 6 using the alkali solution, and made up to 100% with water. The emulsion was found to be thicker than the product of Example 1, but still showed the same rheological properties when applied to the skin. Example 7 - Cleansing lot ion Oil phase w/w% POE (2) stearyl alcohol 2.0% POE (21) stearyl alcohol 1.0% Dimer acid (available from Unichema International under the Trade Name "Pripure 3780") 1.1% Cholesterol USP 0.15% Ceramide (available from Sederma under the Trade Designation "H03") 0.04% Light liquid paraffin 0.20% Heptamethyl nonane (available from ICI under the Trade Name "Arlamol HD") 0.40% Aqueous phase w/w % Aqueous sodium hydroxide solution (1M) to pH 6.0 Water to 100% The product was formulated substantially as described in Example 1. The finished product was sprayable and when rubbed into the skin it exhibited some thickening but did not impart the heavy 'drag' sometimes seen with Example 1 above. The final skin feel before and after washing was almost identical to that obtained by use of the formulation of Example 1. Exa 1e 8 - Barrier cream Oil phase w/w % POE (2) stearyl alcohol 12% POE (21) stearyl alcohol 5% Dimer Acid (available from Unichema International under the Trade Name "Pripure 3780") 5% Cholesterol USP 1% Oleopolymeric emollient (available from Croda Chemical under the Trade Name "Supermol S") 1.5% Beeswax substitute 0.75% Silicone fluid (300 centistokes) 2% Arachidyl propionate (available from Nobel under the Trade Name "Waxenol 801") 1.5% Ceramide (vegetable origin) available 0.75% from Sederma Heptamethyl nonane (available from ICI under the Trade Name "Arlamol HD") 0.5% Aqueous phase w/w% Aqueous sodium hydroxide solution (IM) to pH 6.0 Water to 100% The product was formulated substantially as described in Example 1. The finished product was too thick to be sprayable but still exhibited the rheological properties described above in respect of Example 1 and formed a highly protective layer on the skin. Example 9 - Anti-perspirant emulsion Oil Phase w/w% POE (2) stearyl alcohol 2 POE (21) stearyl alcohol 1 Dimer Acid (available from Unichema 1 International under the Trade Name "Pripure 3780") Di-isopropyl adipate 3 PPG (15) stearyl ether (available from 3 ICI under the Trade Name "Arlamol E") Cyclomethicone (available from Dow Corning 5 under the Trade Designation "DC345") Aluminium chlorhydrate (available from 5 Reheis, Ireland under the Trade Name "Micro-Dry") Aqueous Phase Water to 100% Method The oils were heated to approximately 75°C to produce a clear liquid. The cyclomethicone was then added and the resulting mixture subjected to high shear mixing. The aluminium chlorhydrate was then added with continued high shear mixing. The water was heated to approximately 75°C and to this were added the oils (re-heated to 75°C) with continued high shear mixing for about 10 minutes. The resulting mixture was cooled rapidly (by so- called "crash" cooling) with continued mixing to provide the desired product. The emulsion obtained comprises a stable white milky fluid with suspended, oil-bound aluminium particles. Microscopic examination showed these to be within liquid crystalline arrays. Delivery of this emulsion from a roll-on provides a quick-drying anti- perspirant with good skin feel properties. Dispensing the emulsion via a "roller" mechanism gives a shearing action so that the product is delivered in a ready-thickened state on the skin.

Claims: CLAIMS 1) A cosmetics, pharmaceutical or toiletries composition comprising a dicarboxylic acid of the formula I R i -CH-R- j -CO j H ^ R 3 -CH-R 4 —C0 2 H (or an acceptable salt thereof) wherein R^ and R3 are each independently Cg to C^ Q alkyl and R2 and R4 are each independently Cg to C ] _ Q alkylene, with the proviso that the acid may contain one or more unsaturated carbon-carbon bonds. 2) A composition as claimed in Claim 1 wherein R- j _, R2, R3 and R4 all have the same chain length. 3) A composition as claimed in Claim 2 wherein the dicarboxylic acid is dilinoleic acid. 4) A composition as claimed in any one of the preceding claims wherein the dicarboxylic acid is present in an amount of from about 0.1% to about 30% by weight of the composition. 5) A composition as claimed in Claim 4 wherein the dicarboxylic acid is present in an amount of from about 0.2% to about 10% by weight of the composition. 6) A composition as claimed in any one of the preceding claims in the form of a sunscreen formulation comprising a sunscreening agent. 7) A composition as claimed in Claim 6 wherein the sunscreening agent is present in an amount of from about 0.1% to about 10% by weight of the composition. 8) A composition as claimed in any one of the preceding claims which is substantially free of spherical bilayer or multilayer membrane vesicles. 9) A composition as claimed in any one of the preceding claims in the form of an emulsion. 10) An emulsion comprising a dicarboxylic acid of the formula (I) R-. -~ c H """ Rp """"" C O H R 3 — CH -R 4 — C 0 2 H wherein R- j _ ar.d R are each independently Cg to C-J_Q alkyl and R2 and R^ are each independently Cg to C-J_Q alkylene; with the proviso that the acid may contain one or more unsaturated carbon-carbon bonds (or an acceptable salt thereof) ; and an effective amount of an emulsifying agent chosen such that the emulsion may be shear- thickened in use. 11) An emulsion as claimed in Claim 10 wherein the emulsifying agent is an alkoxylated emulsifier. 12) An emulsion as claimed in Claim 11 wherein the emulsifying agent is an alkoxylated C^ 4 to C22 alkanol. 13) An emulsion as claimed in Claim 12 wherein R- R2 R 3 and R 4 all have the same chain length. 14) An emulsion as claimed in .Claim 13 wherein the dicarboxylic acid is dilinoleic acid. 15) An emulsion as claimed in any on Claims 10 to 14 wherein the emulsifying agent is a mixture of alkoxylated C 14 to C 2 2 alkanols having different hydrophilic/lipophilic balances (HLBs) . 16) An emulsion as claimed in Claim 15 wherein the emulsifying agent is a mixture of a polyethoxylated C^ to C 2 2 alkanol bearing a chain of 2 to 10 ethoxy groups (HLB between about 4 and about 12) and a polyethoxylated C 14 to C 2 2 alkanol bearing a chain of 10 to 40 ethoxy groups (HLB between about 10 and about 20) . 17) An emulsion as claimed in Claim 16 wherein the emulsifying agent is a mixture of POE (2) stearyl alcohol and POE (21) stearyl alcohol in a ratio of about 2:1. 18) An emulsion as claimed in any one of Claims 10 to 17 wherein the emulsifying agent is present in an amount of from about 0.5% to about 20% by weight of the emulsion. 19) An emulsion as claimed in any one of Claims 10 to 18 wherein the dicarboxylic acid is present in an amount of from about 0.2% to about 10% by weight of the emulsion. 20) An emulsion as claimed in any one of Claims 10 to 19 wherein the emulsifying agent and the dicarboxylic acid are present in a weight ratio of about 5:1 to about 1:1. 21) An emulsion as claimed in any one of Claims 10 to 20 wherein the emulsion is an oil-in-water emulsion. 22) A cosmetics, pharmaceutical or toiletries composition as claimed in any one of Claims 1 to 9 comprising an emulsion as claimed in any one of Claims 10 to 21.

Inventors: BARTON STEPHEN PETER, BARTON, STEPHEN, PETER
Applicants: BARTON STEPHEN PETER, BOOTS CO PLC, BARTON, STEPHEN, PETER, THE BOOTS COMPANY PLC
Application year: 1994
Main classification: A61K7
IPC codes: A61K8, A61K31, A61Q5, A61Q15, A61Q19